Mirmo (ミルモ/Mirumo) is an adorable, blue Muglox who loves chocolate and the fairy protagonist of the story. He just creates mischief instead of helping Katie. He comes out of the blue mug. He is so selfish when it comes to chocolates and Kumo!cho. Mirmo is Rima's fiance. He is Mulu's brother. He is Yatch's rival. He has a blue hat, yellow hair, blue apparel, white collar and dark blue shoes. His age is unknown. He has a height of 10 cm (centimeters).
Mirmo is a cute muglox who loves chocolate and is playful but at times, selfish and lazy. Although he is Rima's fiance, he refuses to marry her because he only likes her as a friend, but does not love her. He is Katie's partner and Yatch's rival. He uses a pair of maracas as his magic tools. He's the prince of the Muglox World, and is Murumo's older brother. As a member of the Royal Family, he can turn humans into fairies for 24 hours. His specialty (for attacking) is butt attack (ketsuatatsuku).
Mirmo first appears in the Muglox World. Mirmo was called by his father and his father says that he must go to the Human World. Mirmo doesn't like, so his father made a decision: Mirmo is going to marry Rima, his fiancee. Mirmo doesn't like, so he runs away from the Muglox World. He visits a mysterious cave and then he enters it. But he was teleported by the blue mug. His assigned mug is the blue cocoa mug. Katie announces her wish and then the cute Mirmo appears! At first Katie was afraid but then she understands he is a Muglox. Katie showed him to her mother, but it seems that Katie's mother is unaware of mugloxes. Katie did everything but Mirmo disagrees. Katie called herself pathetic/coward... But Mirmo understood her, so he doesn't hate humans anymore.
Mirmo defeats Darkman because Saori was under control of Darkman. With a little help from Saori, he was defeated for good and then evil is stopped.
Katie uses Mirmo for cellphone collecting session. He uses his magic to collect crystals. He wishes that he eats a lot of Kumo!cho.
He tried to convince Katie to meet Dylan so that their wish would come true but Katie disagrees because she will lose him. He then uses his magic to temporarily erase Katie's memory of Mirmo leaving her when her wish comes true. During his last remaining minutes in the Human World, he decides to find Katie to bid her goodbye but when he sees Katie he is about to disappear and never has the chance to say goodbye. All he does is shout out Katie's name. He is then punished for not returning to the Muglox World and becomes a rabbit. Katie takes care of him and tries her best to bring Mirmo's memories of being a Muglox to bring him back to his natural self.
- Mirmo's angel outfit 1
- He uses this in one episode.
- Mirmo's angel outfit 2
- He uses this in one Charming episode. He sings as an angel while Katie is crying.
- Mirmo's marjorette outfit
- He wears this in one episode. He is spinning a stick (of course)
- Mirmo's flower queen outfit
- He wears this in Episode 7 to repair Katie's loving heart.